Hi Andy – I have a double RB seat unit hanging in my garage – was on my RB when I bought it – looks fine but it needs painting again now – only issue I see with it is that the lower section that screws on either side of the battery at the bottom needs a threaded spacer to link to. I’m guessing that the shape from behind the tank to the lower mounting point was too ‘steep’ for it to be metal bashed to the right spot.
If anyone wants it then let me know.. 
Cheers.. Glenn